/**
 *    Copyright (C) 2020-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
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 */

#include "mongo/db/exec/trial_period_utils.h"

#include "mongo/db/query/find_command.h"
#include "mongo/db/query/query_knob_configuration.h"
#include "mongo/db/shard_role/shard_catalog/collection.h"

#include <algorithm>


namespace mongo::trial_period {

double getCollFractionPerCandidatePlan(const CanonicalQuery& query, size_t numSolutions) {
    const double collFraction =
        query.getExpCtx()->getQueryKnobConfiguration().getPlanEvaluationCollFraction();
    const double totalCollFraction =
        query.getExpCtx()->getQueryKnobConfiguration().getPlanTotalEvaluationCollFraction();

    return std::min(collFraction, totalCollFraction / numSolutions);
}

size_t getTrialPeriodMaxWorks(OperationContext* opCtx,
                              const CollectionPtr& collection,
                              int maxWorksParam,
                              double collFraction) {
    size_t numWorks = static_cast<size_t>(maxWorksParam);
    if (collection) {
        numWorks =
            std::max(numWorks, static_cast<size_t>(collFraction * collection->numRecords(opCtx)));
    }

    return numWorks;
}

size_t getTrialPeriodNumToReturn(const CanonicalQuery& query) {
    // Determine the number of results which we will produce during the plan ranking phase before
    // stopping.
    size_t numResults =
        query.getExpCtx()->getQueryKnobConfiguration().getPlanEvaluationMaxResultsForOp();
    if (query.getFindCommandRequest().getLimit()) {
        numResults =
            std::min(static_cast<size_t>(*query.getFindCommandRequest().getLimit()), numResults);
    }

    return numResults;
}
}  // namespace mongo::trial_period
